Breech-bolt stop



G. HAMMOND.

BREECH BOLT STOP.

APPLICATION FILED 020.1, 1917.

1 ,359,366. Patented Nov. 16, 1920.

I N VEN TOR.

iA f'TokNEY.

7 GRANT HAMMOND, or new HAVE ALVAVC. WASHBURNE, or PIT'ISFIEL CQNNECTICU'I, ASSIGNOR F r ri ONE-THIRD. TO 1), :MASSACHUSETTS, AND ONE-THIRD TO FREDERICK G. CRANE, 0F DALTON, MASSACHUSETTS.

BREECH- BOLT STOP.

' i Application filed December ToaZZ whom it may concern Be it known that I, GRANT HAMMOND, a citizen of the United States,.residing at New Haven, in the county of New Haven and State of Connecticut, have invented a new and Improved Breech-Bolt Stop, of which the following is a specification.

My invention relates to the class of devices employed for determining the amount of movement of a breech-bolt in a firearm, and more especially a firearm of automatic type, and an object of. my invention, among others, is to provide a breech-bolt stop that shall be durable in constructionand efiicient' in its operation. V

One form of device embodying my in vention and in the construction and use of which the objects herein setout, as well as others, may be attained, is illustrated in the accompanyingdrawings, in which- 7 Figure 1 is a view in side elevation of the :upper rear portion of a firearm embodying made 'to such application for "standing that may be desired as to the con my invention. V v Fig. 2 is a view in cross section through the same on plane denoted by dotted line 2-2 of Fig. 1.

The invention illustrated and described hereinfisfa modification of an invention comprised in my copending application filed concurrently herewith and serially numbered 204,921, and reference is hereby any under struction and operation of the firearm aside from the parts embodying this invention.

In the accompanying drawings the numeral 5 indicates a frame including the handle, of my improved firearm, 6 a re ceiver, 7 a barrel secured to the receiver, 8 a trigger guard, 9 a trigger and 10 a hammer, all of which parts may be of any desired construction, the trigger being connected with the hammer controlling mecha nism in any desired manner and the firing mechanism being of any desired type, but including a breech-bolt 11 that is mounted for' reciprocating movement in a breechbolt chamber in the receiver, the invention being especially applicable to a firearm in which movement of the breech-bolt is partially caused by the gases of explosion.

A breech-bolt stop 12 is movably secured in a hole in the side of the breech-bolt, in the preferred form of construction this Specification of Letters Patent.

Patented Nov. to, iaao.

1,1917. SeriaI No. 204,925.

opening and the stop extending across a firing pin 13, the stop having a groove '14: through which the firing pin extends and a recess 15 to receive a spring 16 by means of which the stop is held in its operative position to control the movements of the breech-bolt. In the preferred form of construction the spring 16 rests against a spring seat 17 movably located in the recess 15, the end of said seat resting against the bottom of the hole in the breech-bolt in which the parts just described are located.

it is essential that the stop shall be prevented from unintentional releasing move ment, and to this end I provide means that will effectually secure this result. In the construction herein shown for attaining this end, I provide a lock groove 18, preferably on the under side of the stop and preferably of a more or less V-s hape, and I also pro vide, alip 19,0f similar shape on the bottom edge of theejection opening 20 in the side of the receiver,'thislip being located in the'locking groove and effectually retaining the breech-bolt stop in place, In order, however, that the stop may be released from the ejection opening to permit re moval of the breech-bolt from the receiver, 1 provide a releasing notch 21 in the lip 1:), this notch being preferably of a width not muchgreater than the diameter of the stop 12, so that: the latter can be moved inwardly: to "release the-groove and lip 18 and 19,, one from the other, only when the stop is. in a predetermined position, and preferably Iilo'cate this notch aboutmidway between the ends of the ejection opening 20. With the parts thus arranged it will be perceived that. the positionat which the step may be released is not a normal position of rest of the breech-bolt in which positions of rest there would be the greatest liability of accidental release of the stop, but the releasing notch is so located that in operation the stop is. always rapidly moving past such point, and it will not remain at such point when the parts are in working order.

In accordance with the provisions of the patent statutes, I have described the principles of operation of my invention, together with the device which I now consider to represent the best embodiment thereof; but I desire'to have it understood that the device shown is only illustrative and that the invention may be carried out by other means.

I claim 1. A firing mechanism for a firearm including a breechbolt movably mounted in a breech-bolt chamber in the firearm, a breech-bolt stop projecting from the breechbolt'into an opening in the firearm, to limit the backward movement of the breech-bolt, said stop being attached to said breech-bolt and movable independently thereof for disengaging action, said stop and opening having intereng'aging parts to prevent disengagement of said stop when 7 the breechbolt is normally at rest, and means to permit release of said interengaging parts when the breech-bolt is in an abnormal position.

2,v A firing mechanism for a firearm includinga breech-bolt movably mounted in a breech-bolt chamber in the firearm, a breech-bolt stop projecting from the breechbolt into an opening in the firearm, to limit the backward movement of the breech-bolt, said stop being attached to said breech-bolt and movable independently thereof for disengaging action, said stop having a groove,

a lip upon the edge of said opening to enter said groove to retain the breech-bolt stop from releasing movement when the breech-bolt is in a normal osition of rest, and a releasing notch in said lip to permit release of said stop when the breech-bolt is in an abnormal position.

3. A firing mechanism for a firearm including a breech-bolt movably mounted in a breech-bolt chamber in the firearm, a breech-bolt stop projecting from the breechbolt into an opening in the firearm, to limit the backward movement of the breech-bolt, said stop being attached to said breech-bolt and movable inde endently thereof for disengaging action, said stop and opening having interengaging parts to prevent disengagement of said stop when the breech-bolt is in certaln positions, and means to permit release of said inter engaging parts when the breech-bolt is in substantially one position only. I

4. A firing mechanism for a firearm includin a breech-bolt movably mounted in a breech-bolt chamber in the firearm, a breechbolt stop projecting from the breech bolt into "an opening in the firearm, to limit the backward movement of the breech-bolt, said stop being attached to said breech-bolt and movable independently thereof for disengaging action, said stop and opening having intercngaging parts to prevent disengagement of said stop when the breech-bolt is in certain positions, and means to permit release-of said interengaging parts when the breech-bolt is inan intermediate position.

5. A firing mechanism for a firearm including a breech-bolt movably mounted in a breech-bolt chamber in the firearm, a breech-bolt stop projecting from the breechbolt into an opening in the firearm to limitgroove, said lip having an unlocking notch to permit releasing movement of said stop. when the breech-bolt is in an intermediate.-

position. I

7. In combination with the frame of a firearm having an ejection opening in'one, 'side thereof, a firing mechanism including a breech-bolt movably mounted in the breech-bolt chamber in said firearm, a

in the firearm, a

breech-bolt stop projecting from the breechbolt into said ejection opening to limit rearward movement of the breech-bolt therein, said stop and opening having interengaging parts to rest, and means to permit release of said inprevent disengagement of said, stop when the breech-bolt is normally at;

terengaging parts when the breech-bolt is in, i

an abnormal position. 7

GRANT HAMMOND, 

